Note 4 - Goodwill and Intangible Assets - Changes in the Amount of the Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Balance	$ 6,944	$ 8,201
Amortization	(1,233)	(1,257)
Balance	$ 5,711	$ 6,944

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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